1. Field of the Invention
The present invention relates to a voice information service system, or more particularly, to a voice information service system to be connected to an ATM network for providing a voice information service to numerous users via the ATM network.
In recent years, technologies supporting communication networks have changed from technologies for analog transmission to those for digital transmission or from technologies for a synchronous transfer mode (STM) to those for an asynchronous transfer mode (ATM), have tended toward high-speed and large-capacity communication, and have enabled image communication as well as existing communication of voice and data. The fundamentals of communications are being prepared step by step in pursuit of realization of an advanced information society.
Now that a broadband integrated services digital network (B-ISDN) is prevailing, the present invention provides a means for realizing a service of providing voice information, that is the basis of communication, at lower cost than a known voice information service system while making the most of the features of the B-ISDN.
2. Description of the Related Art
For providing an existing voice information service, numerous telephone terminals are accommodated in a network (a switching network capable of handling analog signals or STM digital signals), and a system (IP system) owned by an information provider (IP) is also accommodated as a terminal in the network. In this case, the IP system is, for example, a system for not only rendering a voice information service for providing time, weather forecasts dependent on local districts, and the like, but also for providing various kinds of voice information such as news for a fee.
To receive a voice information service, a subscriber of a telephone terminal dials a number set in the IP system. In this case, various dial numbers are associated with various voice information services; XXX for a time service, YYY for a weather forecast service, and a predetermined number for news. The network carries out switching and connection according to a dialed number and thus links the telephone terminal to the IP system. The IP system reads accumulated message information upon call termination. The telephone terminal receives the information. After the reception, the telephone terminal clears the call.
As mentioned above, in the known system for rendering a voice information service, the communication network operates in STM. The side of rendering a service and the side of receiving the service must be linked on a one-to-one basis during information transmission. Equipment such as a trunk to be included in an exchange must be installed for each user. In other words, if the number of trunks each having complex facilities is decreased, the probability of a line being busy rises. If numerous trunks are installed, there arises a problem that the operation rate deteriorates and cost increases.
In contrast, when systems each shared by a plurality of users are employed, even if access is gained to a system, much information cannot be heard from the start thereof because of a competitive situation.
There is the trend of communication networks toward B-ISDNs. Under the circumstances, voice services are still important services. With the advent of a communication network having the feature of high-speed and large-capacity communication, an information communication fee must be lowered.